Draw press



y 30, 1933- R. J. PARDEE 1,911,385

DRAW PRES S Filed April 9, 1932 4 Sheets-Sheet l gnmmmion abbow v.

Ma 30, 1933. A E 1,911,385 DRAW PRESS Filed April 9, 1932 4 Sheets-Sheet 2 I ,Z -y 'i A I H v z 1 XL M /u/ May 30, 1933. R J; PARDEE 1,911,385

DRAW PRES S Filed April 9, 1932 4 Sheets-Sheet 4 Patented May 30, 1933 UNITED STATES PATENT.

- nomzn'ra. PARDEE, or CLEVELAND HEIGHTS, OHIO, Assieivoii "rerun or forming In draw presses roncn a SHEARPWORKS COMPANY,

Application filed April 9,

presses and more particularly to a draw press" in which the blank holder andthe draw ng 2 die are operated from the slide andthe blank holder is yieldably connected with the slide so as toyield when the pressure on the blank holder exceeds apredetermined amount."

heretofore generally known it has been customary to drive the formin die and blank holder from the main shaft of the press. It also has been customary to cause the blank holder to dwell for a definite period in holding contact with the work during the drawing or punching operations. These links and levers have usually been complicated in construction and-design and expensive to manufacture. "In order to slmpllfy thefconstruction and operation and to reduce the cost of manufacture, I have provided'a draw press in which the blank holder and forming die are both driven from thesame connecting rod and in which the blank holder is yieldably or slidably mounted within the slide so that the pressure of the blank holder against the work is constant but may be varied, if desired.

One of the main objects of the invention therefore is to simplify the construction and design of a draw press and to provide a draw press in which the number of parts are reduced to a minimum and the cost of production is likewise reduced.

Anotherobject of the invention is to pro vide a draw press in which the forming die and blank holder are both operated from the slide and in which a hydraulic yieldable con- 7 nection is provided between the blank holder and the slide whereby the blank holder may yield when the pressurethereon exceeds, a predetermined amount.

Another object of the invention is to provide a draw press of the character described in which the blank holder is slidably and yieldably mounted in the slide and connected with the accumulator by means of a rigid connection which extends into the slide and permits movement of the slide with respect thereto.

DRAW providea system of links and levers to V or CLEVELAND, 01-110, aconrone'rion or PRESS 1932. Serial No. 604.239;

Further and more limited objects of'the" invention will appear as the description proceeds and by"rcference to the accompanymgdrawmgs nwhich- Fig. "1 is a'view in front elevation of my improved draw press; Fig. 2 IS a vertlcalsecti'onal V ew; F1g,;3 is

of the draw'press'jis a shaft 4 having a crank portion 5 to which isconnected a connecting rod- 6. The press is adapted to be operated by means ofa motor 7 which drives a gear 8 mounted on a'shaft 9 which in -turn drives the drive shaft 4 through suitable mechanism including the large gear'10.; Slidably mount-- ed on the draw press isa cross head or slide 11 which is disposedbetw'een guide blocks 12 and 13. The cross head or slide 11 is operatively connectediwith the crank portion 5 of the shaft 4; by means of'a connecting rod 6 and pin 6*. The slide is provided with a cylindrical opening 14: in which is mounted slide 11 is provided at one side thereof'witli a chamber 21 which is connected withthe cylindrical opening 14 by means of a here or assa ewa .22..

. Disposed at the top draw press Referring now to; the I drawings; the draw press consists essentially of a base member 1 on which is mounted a die block 2whic'h supg portsa die 3. J ournaledin the upper portion extending transverselythereof is a-supp'ortv ing baroor member23having'an opening therein-through which extends a rigid tubu-i lar connection 24 having an opening 25 therein. a bore or opening provided in {theslide 11 and the. opening25 is disposed in constant open communication with the chamber 21." The tubular member 24 issecured in place'by means of a nut 26 and the axis of theftubular The tubular member 24 extends through 7 member is disposed parallel to the direction of movement of the slide. Suitable packing glands 27 and 28 are provided about the tubular member to prevent leakage thereabout. Connected with the upper end of the tubular member 24 is a rigid connection'29 which is secured to the tubular member 26 by means of a union 30. The connection 29 leads to an accumulator the purpose of which will be hereinafter described. 1 j

"The'slide or cross head 11 is reciprocated by the shaft 4 and crank 5 and has a working fit with the tubular member 24 which extends therethrough. The blank holder 18 is operatively connected with the piston 15 and is adapted to engage the work and hold-it in position on the die 3. The slide 11 has a fixed stroke determined by the length of the crank 5. The work is positioned on the die 3 and as the slide moves downwardly, the blank holder 18 engages the work while the forming die 17 continues its downward movement and produces the drawing operation.

The rigid connection 29 connects with an accumulator 31 from which leads a connection 32 which connects with a pressuretank 33. The connection 29 is provided. with a pressure ind-icator 34 and a manually oper- .able valve 35. Leading downwardly from the accumulator 31 is a tubular connection 36 to which thelower end of the connection 29 is secured. From the construction and con-,

nections just described, it will be seen that the opening 14 .into which the piston 15 is slidably securedis in constant open communication with the accumulator 31..

Due to the high pressure frequently obtained inthe accumulator and in the connections between the accumulator and the space in front of the piston 15, it becomes necessary toprovide the rigid connections just described. i V V In the ordinary operation of the draw press a predetermined pressure is supplied to the air pressure chamber 33 which in turn exercises a predetermined pressure upon the accumulator 31 which preferably contains a liquid. This'pressure is also exerted upon the piston 15 when the valve 35 in the connection 29 is open. It will therefore be seen that the pressure on the blank holder is constant and the same as the pressure within the accumulator. This pressure of course can be varied by varying the pressure within the accumulator and when the pressure on the blank holder exceeds amount, the blank holder may yield or move with respect to the slide. Upon the upward movementof the slide, the enlarged portion 1'2 of the forming die engages the piston 15 and moves'iwith the slide from the position shown in Fig. 3' to the position shown in Fig. 2,

It will now be seen that Ihave provided a a I predetermined Various changes may be made in the details of construction and arrangement of parts without departing from the spirit ofmy invention and the embodiment of the invention hereindisclosed is merely illustrativeand not to be considered in a limiting sense as the invention is limited only in accordance with the scope of the appended claims.

Having thus described my invention, what I claim is: I

1. In a draw press, the combinationof a shaft, a'slide operatively connected with said shaft so as to be reciprocated thereby and having a forming die rigidly connected therewith, a blank holder slidably mounted in said slide, an accumulator, a connection between said accumulator and said blank holder so as to permit a movement of the blank holder with respect to said slide, said connec-; t1on including a conduit extending through said slide and dlsposed 1n open ,commun1ca-,

tion with the space in front of said blank holder. I V

2. In. a draw press, the combination of a shaft, aslide operatively connected with said shaft and slidably supported'on the frame of the press, an accumulator, a connection leading from said accumulator and extending through said slide, a forming die rigidly connected with said slide, said slide having an opening therein, a piston yieldably mounted in said opening, a blank holder operatively connected with said piston, means connecting said connection with the opening in said slide in front of said piston whereby said piston may move with respect to said slide when the pressure exceeds a predetermined amount.

3. In a draw press, the combination of a shaft, a slide operatively connected with said shaft so asto have a fixed stroke and having a forming dieconnected therewith, said slide.

havin an opening therein, a blank holder slidably mounted in said opening and adapted for movement with respect to said slide, an accumulator, and means providing a constant open communication between said accumulashaft so as to have a fixed stroke and havinga forming die connected therewith, said slide having. an opening therein, a blank holder slidably mounted insaid opening and adapt ed for movement with respect to said slide, an accumulator, and means providing a constant a rigid conduit ex open communication between said accumulator and the space in front of said blank holder and including a rigid conduit extending through said slide and connected with said opening.

In testimony whereof, I hereunto aflix my signature.

ROBERT J. PARDEE. 

